To compare the fficacy of lamivudine vs. placebo vs. lamivudine followed by the combination of intron A plus lamivudine in patients with chronic hepatitis B infection who are interferon alpha non-responders. There will be two primary efficacy variables: histological response (for cmparison of the monotherapy regimes) and seroconversion rates (for the comparison of the placebo and comb-ination reginesm). Complete or partial normalization of serum alanine amino-transferase (ALT) and HBsAg seroconversion will be secondary markers of efficacy